Thread forming mechanism



Nov. 30, 1937. F. NELL THREADFORMING MECHANISM Original Filed June 16, 1936 2 Sh'eets-She?) 1 M v f f M MN QM 3 0M N QM 5-: Qnv \x Q\ Nov. 30, 193-7..

THREAD FORMING MECHANISM Original Filed June 16, 1956 2 Sheets-Sheet 2 2a 98 a9 ma m /a F. NELL l 2,100,449

Patented Nov. 30, 1937 UNITED STATES PATENT OFFICE 7 2,100,449 THREAD FORMING MECHANISM Frederic Nell, Waynesboro, Pa., assignor to Lanflis Machine Company, Waynesb ration of Pennsylvania.

oro, Pa., a corpo- Original application June 16, 1936, Serial No. 85,563. Divided and this application December. 28,;1936, Serial No. 117,947

12 Claims. (Cl. 10145) pending application Serial No. 85,563, filed June 16, 1936, which application is a continuation in part 01 my copending application Serial No. 7 5,129 filed February 5, 1935.

Throughout this specification the term chaser is used in its broad as well as its limited sense. That is, it may mean the actual cutting tool and its carrier or holder, or the definition may be confined to the cutting element alone.

It is a primary object of the present invention to devise a thread-cutting machine having a series-of slidable chasers detachably connected with a cam element, in association with means for ,accurately positioning all of the chasers simultaneously so that during assembly, in a single movement of the cam element, it will readilyand assuredly pick up all of the chasers for intercon nection therewith. More specifically, the present invention contemplates carrying out the preceding object where the cam element is, centrally disposed and designed, upon axial movement, to positively move the. chasers'radially in both directions. It is'another major object of this invention'to provide new and improved means for adjusting a chaser-controlling cam element relative to its operating means. In this connection it is an object to provide an adjustment feature which permits the removal of the chasers for sharpening without in any way dismantling the machine proper.

It is a further object of this invention to provide an improved means for firmly mounting and guiding the chaser controlling element for axial movement in the head whereby strain on the cam portions thereof is eliminated and binding and sticking of the same is hence obviated.

It is another important object of the present invention to devise a thread-cutting machine having a set of removable chasers which may be replaced accurately without disturbing the original setting of themachine and therefore without requiring trial cuts to place the machine in condition to cut the same size threads.

I n It is a further object of my invention to devise a thread-cutting machine comprising a main body and a detachable head designed to carry chasers, with a chaser-positioning cam that is fully retractible to permit very quick chaser removal and immediate substitution of heads oi! different sizes.-. i v

The foregoing and further objects oi. the pres ent invention will clearly appear upon a consideration of the following detailed description when taken in. conjunction with the. accompanying drawings wherein:

Figure 1 represents a fragmentary longitudi- .nal section taken vertically through the front. vportion of a collapsible tap comprising a preferred form of the present invention with the parts disposed: so as 'to extend the: chasers to nd with some 0! the times.

Figure 4 isia'sectionalview similar to Figure ,1, but showing the partsin the positionthat they assume when the chasers are collapsed.

Figure 5 is. a section-corresponding to Figures 1 and 4 but with the chaser-controlling cam so adjusted as to be completely retractedto permit ready removal of the chasers.

The improvements andadditions illustrated in the drawings and aboutto be descrlbedare disclosed in association with collapsible taps ofthe type shown in Newman Patent No. 1,811,802 and my copending application Serial No.. 15,129,

that it takesafter being sharpened a number of n aforementioned; and ,although. these are desir- .able forms it will be appreciated that my improvements and additionsmayv be used on many other thread forming machines within the knowledge of' those skilled in the art and within the scope of the appended claimsr With furtherreference to thedrawings wherein like numerals are employed to designate like parts and with particular reference for the moment to Figures 1 and 2, the foundation or the main body structure of the preferred embodiment of this i'nvention'comprises an elongated hollow body 15, of which a portion only is shown, and to which is secured a chaser carrying head l6 by means 01 detachable studs ll.. At one end the head l6 car-. ries a plurality of cutting elements in the form of circular chasers 19 secured to radially slidable chaser holders 20. The holders 20 are insertible through, and radially slidable within, a correspending series of T-slots 22 in the front face or head I6, and at their inner ends are provided with fingers 23 which form with the bodies of the holders a series of cam slots 23a. The holders 20 are cut away at 52 for a purpose to be later explained.

The head I6 is hollow and shapedinternally to slidably but non-rotatably receive a tapered chaser-controlling'cam member 24, which has on its periphery a set of inclined integral fingers or wings 26 that cooperate with inclined faces on a series of ribs 36 on the cam body to provide a series of cam grooves 25. The fingers 23 of the chaser holders are snugly received within the grooves 25 of the cam member, and the wings 26 of the cam member are loosely received in the cam grooves 23a of the chaser holders. Therefore, as the cam member is moved forwardly or to the left in Figure 1, the chaser holders will be positively cammed radially outwardly; and vice versa, as the cam member is moved rearwardly, the chaser holders will be positively drawn radially inwardly.

The fingers or wings 26 are formed as integral extensions of the series of radially extending ribs or projections 36 formed on the front end of the cam element 24. The adjacent sides of these ribs meet to produce a series of V-grooves 31 on said cam element. The head I6 is provided with a circular series of radially and "outwardly extending grooves 30 the adjacent sides of which meet to form a series of wedge shaped ribs or projections 42, slightly flattened at their inner ends, and terminating in an axially extending bore 34 in the head I6. Adjacent the rear of these grooves 30 the bore 34 is cylindrical as at 44 and of the same diameter as a bore 46 formed in'the body I5. When assembled the bores and 46 of head I6 and body I are aligned (see Figs. 1, 4 and 5) for a purpose to be later explained.

Just beyond the ribs 36 the camelement 24 is formed with a cylindrical portion 48 of considerably less diameter than the ribbed portion and to the rear of this cylindrical portion is a second cylindrical portion 21 of a diameter equal to that of bores 44 and 46.

When the cam element 24 is assembled in the head I6 and body I5 the'cylindrical portion 21 is snugly received by the bores 44 and 46, see Fig. 1, while the front end of said cam element is rigidly supported both laterally and also against rotation by means of the reception of the ribs or projections 36 by the grooves 30. The grooves 30 and projections'36 are machinedto provide a nice sliding fit and the outer portions '32 of grooves 30 are shaped to receive the wings 26 with clearances 38 and 40 between the tops and one of the sides thereof. It will also be observed that the depth of the groove 25 is greater than the width of finger 23 thereby forming a clearance 39 between the outer face thereof and the bottom of this groove. A similar clearance 4| is left between the face of fingers 26 and thebottomof grooves or slots 23a.

These clearances are shown in an exaggerated manner in the lower portion of Figure 2 when the chasers 20 are removed but are covered by the chasers in the upper portion thereof. The clearance 40 also appears in Figures 1, 4 and 5.

In Figure 1, the bottom of the groove 31 formed by the ribs 36 and the partof the wedge-shaped projection 42 formed by the sides of grooves 30, normally hidden by the other parts, are indicated by dotted lines to clarify these features.

From the above it is seen that the cam element 24 is slidably mounted in the head I6 with two spaced points of lateral support, 1. e. by engagement of the portion 21 with the bores 44 and 46 and by the engagement of theribs 36 with the sides of grooves 30. The large angle between the sides of the projections 42, formed by adjacent grooves 30, prevents wedging or binding and at the same time the interengagement of the ribs 36 and grooves 30 prevents rotative movement of the cam element with respect to the head.

i As noted previously clearances are provided both at the top and on one side of the fingers or wings 26 which carry the cam grooves 25, as well as between fingers 26 and 23 and the bottoms of the slots or grooves 25 and 23a, into which they are received. Thus none of the stresses attendant upon the support of the cam element 24 are transmitted through the fingers 26 or the chasers 20 and binding or sticking of these parts under load is obviated.

The cam member 24 is internally threaded to receive the externally threaded end of a coupling rod 28. As will be seen later the cam member is axially adjustable relative to this rod and may be lockedwith respect thereto in any desired position of adjustment. The rearward end of the rod 28 is peripherally grooved and detachably coupled to an integral forked forward extension 29 of a plunger I30. The plunger I30 is disposed within the bore 46 of the body I5 and is designed for reciprocation therein,

At will be readily understood by those versed in the art the plunger I30 is to be reciprocated by some sort of control mechanism, not shown. As'the general construction and'mode of operation of such mechanisms are well known no further description is deemed necessary. However, reference is made to the Newman Patent No. 1,811,802 for an illustration and description of a typical form 01" earn element operating mechanism and also to my aforementioned ap-.

plicationSerial No. 85,563, which discloses and claims improvements in suchmechanisms. It

should be understood, however, that the cam element control or operating mechanism forms no part of the present invention and the same the threaded rod 28. The meansfor effecting this adjustment and for locking the parts in adjusted position are as follows. The forward end of the 'rod 28 is tapped to receive an externally threaded sleeve 96 which extends slidably through the front end of the cam member 24 and which is providedwith a head 91 that can be rotated by an actuating tool. The threaded portion of sleeve 96 has a transverse slot therethrough which receives a pair of diametrically opposed brake shoes 98 that are slidable radially in the slot and that may be forced outwardly into locking engagement with diametrically opposite portions of the tapped bore of rod 28 by rearward motion of a tapered stem 99 that fits betweenthe shoes and forms an integral part of a. manually adjustable screw I00. Screw I00 is threaded into the sleeve 96 and may bemanually operated by inserting a tool through the hollow head 91 of the sleeve 96.

To effect an adjustment, screw I00 is loosened to unlock the brake shoes 98 and the sleeve 96 is rotated within the rod 28 to obtain the desired relative disposition of each part, after which the screw I00 is again locked to expand the brake shoes 98. For preventing rotation of the anism is substantially identical with that shown in Newman Patent No. 1,912,298.

The adjustment just described accurately determines the thread diameter because it definitely locates the head 01 longitudinally of the device, and the head 91 in turn definitely locates the cam member 24, for in actual working positions as illustrated in Figures 1 and 4 the forward end of the cam member is always tightly in contact with the rear end of the head 01. This contact is obtained, not through rotation of the cam member which can only slide in the head I6, but through bodily rotating as a unit all of the screw-threaded elements which are housed within the cam member 24. Upon tightening the screw I to lock' the brake shoes 98, the manipulation of the head 01 with the proper tool will cause the sleeve 96, the screw I00 and the rod 28 to rotate -as a unit within the cam member to advanceor retract the latter depending upon the direction of rotation of the head 81. This manual operation is permitted by the yielding latch mechanism I02 to I which, however, has suflicient resistance to rotation to prevent any inadvertent bodily rotation of the screw-threaded elements to get the cam member outof adjustment.

In Figure 5 the cam member 24 is shown sufliciently retracted, by [the adjustment just described, to take the cam fingers or wings 26 out of overlapping engagement withthe complemental fingers 23 of the chaser holders, thus permitting the chasers to be readily withdrawn radially for sharpening, adjustment or repair. A chaser. is shown partly removed in Figure 5, and in Figure 3 there is shown a removed chaser having its' cutting element resharpened. Due to the fact that removal and replacement of the chaser does not involve any'alteration of the position of the head .91 longitudinally relative to the plunger 30, the chasers may be replaced and the screwthreaded elements bodily rotated to bring the cam 24 into engagement with the rear end of the head 91, thus assuredly bringing the parts exactly in the same position that they previously had prior to removal of the chasers. Hence, operation of the machine may be resumed to cut threads of exactly the same size, and this is important because it eliminates any trial and error adjustments and trial cuts with attendant loss of time and possible slight inaccuracies.

A highly important feature of this invention resides in the provision of means for facilitating a quick coupling between the cam members and the chaser holders upon insertion or replacement of the latter. As seen in Figures 1, 2, 4 and'5, the body of the cam member 24 has a plurality of flat inclined faces 50 corresponding in number to the number of chasers. .The inclined faces terminate in forward extensions or ledges I06, as

best seen for example in Figures 1, 4 and 5, which project forwardly va slight distance beyond the forward extremities of the cam wings 26. Therefore, when the chasers are replaced the holders can be simply pressed radially inwardly until their cam fingers -23 engage ledges I06 in.

which position every oneof the cam fingers 201s accurately located for reception by a corresponding groove 25 of'the cam, and as the adjustment is performed to move the cam member forwardly all of the chaser holders are-pickedup and intercoupled,, simultaneously and without dimculty, to the cam-member. I The cha'serholders 20, are cut .away'as at 52 to providesufilcientclearance for this amount of inwardmovement. 'I his feature is shown but not claimed in my copen'ding application Serial No, 5,129, the claims of which are directed to anothe'r'form of cam member adjus'ting and locking means of the character {above set forth; t,

The head I6 is readily removable from body 15.. Although the cam member-24' is-firmly supported radially in the head I6, it can "readily; slide out of v the same rearwardly. -Access,to thestuds I1 is had by performing the adjustments above described to remove the chasers, "and thereafter, upon removal of-the studs I! the head I6 can be replaced by a" larger or smaller head which also fits the body I5 but, which is designed for use in cutting another range of thread diameters.

The particular means for mounting and adjusting the cuttingelementswith respect to their.

holders formsno'part of the present invention, I but isfully set forth and claimed in my copending' application SerialNo. 23,901,"filed'May 28, 1935.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics I thereof. 'The "present embodiments are therefore'to' -be considered in all respects as illustrativean'dnot restrictive, the

' scopeof the invention being indicated by the ap- -pended claims ratherithan by the foregoing description, and all changes which come within the g meaning and range 'of equivalency of the claims 3 are therefore intended: to be embraced therein.

What is claimedand desired to be secured by United States Letters Patentls:

1. In a thread cutting machine; a head'having a plurality of radially extending guideways therein; aplurality of chasers slidably mounted lnpsaid guideways; an axially shiftable control member mounted in said head; a plurality of radial projections on said control memberhavinginclined camming wings thereon; inclined surfaces o n said member cooperating with said cammingwings to form a" plurality of inclined cam'grooves; said chasers being provided'with projections inter locked with said cam grooves; means for moving said control member to slidejsaid chasersin said guideways; said movement terminating in each direction with said chaser projections interlocked 1 with said grooves; means: for causing relative movement between said moving means and said control member to release saidchaser projections from said-groves; said inclined surfaces being 'extended beyond said radial projections to support said chasers with their'projections aligned with said grooves when in released position.

2. Ina thread cutting machine; a head having a pluralityof radially extending guideways therewardly of said guideways without releasing said cam wings from saidgrooves; said means also being operable to effect further movement of said control member to position said cam wings on said inclined surfaces and out of engagement with said grooves.

"3, Athread-cutting machine comprising a body and a complemental separatehead for the body, a plurality of removablechasers slidably mounted on the head, fastening elements for detachably securing the headto the body, said elements being enclosed behind said chasers but accessible upon removal of the chasers, retractible control means in connection with said chasers to normally prevent their withdrawal, and means projecting externally of the head to permit ready retraction of said controlmeans and removal of said chasers without dismantling any other parts of the machine, a

4. In athread cutting machine, a body adapted to receive any one of several complemental heads of different sizes; the head havingsubstantially radial slideways-for chaser holders-opening towards its front face and recesses extending rearwardly from .said slideways; to the front end of said body; said slideways guiding said chaser holders for movement radially of said head but holding them against movement axially of said head; meansinsertible through said recesses and accessible through said 'slideways, when said chaser holders aremoved radially outwardly, for securing the headto the bodvpand adjustment means for releasing saidchasers from a controlling cam so that said chasers may be withdrawn sufliciently to expose said recesses.

. 5. In a thread cutting machine, a body and a complemental head for the body, a plurality of removable chasers slidably mounted on the head,

securing means for detachably securing the head to the body, said securing means being enclosed behind said chasers but accessible upon removal of said chasers, control means for said chasers including a cam element normally coupled to said chasers and an operating means adjustably connected to said cam element, said adjustable means being operable to retract said cam element and uncouple said chasers thereby permitting re-- moval thereof from said .head and providing access to said securing means without dismantling any other parts of the, machine.

6. In a thread-cutting machine'having slidably mounted chasers, axially shiftable control means coupled to said chasers and'comprising: a support, and a chaser-engaging member in adjustable screw-threaded connection with said support; va device for'causing relative rotation of said memberand said support, said device connected by screw threads to said support to. establish an adjustable stop for limiting axial movement of said memberin one direction; and means for lockingfiasid device, against rotation relative to 'said support, said means comprising a brake shoe carried by said device and an'element for pressing said brake shoe against said support.

7. In a thread-cutting machine having slidable chasers, axially shiftable but non-rotatable control means coupled to said chasers and including a camelement andan operating means, a screw-threaded connection between said element and said operating means an adjustable stop means threaded to said operating means and limiting rrelative adjusting movement of said element and said operating means in one direction, and means tolock said stopmeans to said operating, means whereby said operating means may be rotated thereby relative to said cam element, said locking means comprising friction members carried by said stop means and engaging said operating means.

i 8. In. a thread-cutting machine, the combination set forth in claim 7 wherein said friction members are threaded to cooperate with the threaded connection between said stop means i and said operating means.

9. In a thread-cuttingmachine, a, body portion provided with a head, a cylindrical hole in said body portion,-said head having an axial aperture provided with inwardly extending key members and terminating in a cylindrical recess,

said hole andsaid recess being'of the same diameter and aligned to form a. continuous bore, a chaser controlling element slidablyreceived by said bore and aperture, spaced bearing portions on said element engaging said bore and said key members respectively. a

10. In a thread-cutting machine, a body portion provided witha head, a cylindrical opening in said body portion, an. axial aperture in saidheadterminating at one end in-a cylindrical recess, said opening and said recessbeing aligned and of the same diameter thereby forming. a continuous bore, a' circularseries of axially extending grooves in saidhead opening into said w aperture, a chaser controlling element slidably received by said head and said .body on spaced bearing surfaces, said bearing surfaces comprising a series of radially extending projections carried by one end of said element and snugly g 'and'guiding said chasers, cam fingers on said chasers having inclined inner surfaces, a chaser received by said grooves, and a, cylindrical porcontrolling element provided with a series of projections having inclined outer surfaces carrying portions extending at right angles thereto and-forming'therewith' cam grooves, said projections slidably fitting in 'saidaxial grooves to support said elementindependently of said extending portions, and said cam fingers being re ceived within said cam grooves.

12. Ina thread-cutting machine, an apertured head carrying radially slidable chasers, a

cam-element coupled'to said chasers and slidably supported in said head, a circular series of grooves in said head and a matching series of radial projections on'said element adapted to be snugly but slidably received in said grooves, whereby said element is-rigidly supported in said head against lateral or rotational movement; cam means carried 'by said radial projections and extending at right angles thereto, cooperating cam engaging fingers carried by said chas- "ers and'coupled to said cam means, said grooves being provided with radial extensions of sufficient size to receive said cam means with clearances whereby stress on said cam element is transmitted to said head solely through said radial projections .and binding of said cam 1 obviated.

means and said fingers is I FREDERIC NELL; 

